Rational design of a dual-reactive probe for imaging the biogenesis of both H2S and GSH from l-Cys rather than d-Cys in live cells†

Abstract Biothiols and their interconversion are involved in cellular redox homeostasis as well as many physiological processes. Here, a dual-reactive dual-quenching fluorescent probe was rationally developed based on thiolysis reactions of 7-nitrobenzoxadiazole (NBD) tertiary amine and 7-cyanobenzoxadiazole (CBD) arylether for imaging of the biothiol interconversion. We demonstrate that the NBD-CBD probe exhibits very weak background fluorescence due to the dual-quenching effects, and can be dual-activated by H2S and GSH with an over 500-fold fluorescence increase at 525 nm. In addition,